Browse Prior Art Database

Program Monitoring Alert Mechanism for Microprocessors

IP.com Disclosure Number: IPCOM000086895D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 45K

Publishing Venue

IBM

Related People

Galli, EJ: AUTHOR

Abstract

Software monitoring functions are invoked in a microprocessor under program control, at any desired step in an executing program sequence, by the addition of a new control instruction designated "monitor alert". The new control instruction can be disabled at any time when not wanted, yet is instantly available when needed.

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Program Monitoring Alert Mechanism for Microprocessors

Software monitoring functions are invoked in a microprocessor under program control, at any desired step in an executing program sequence, by the addition of a new control instruction designated "monitor alert". The new control instruction can be disabled at any time when not wanted, yet is instantly available when needed.

Microprocessor engine 5 is attached to memory 1 and to one or more I/O adapters via I/0 interface 2. Optional hardware monitor/test adapter 3 also may be attached via the I/0 interface 2 and/or the memory/EMA (external memory address) interface 4. Control programs and application programs residing in memory 1 include "monitor alert" control instructions at appropriate points in the instruction sequences. In addition to its basic functions, engine 5 contains additional special functions of "software monitor alert detection" and "monitor mode control" logic 6 and 7, respectively.

The monitor alert control instruction (of halfword length) is always followed by a halfword data field which carries programmer-determined information identifying the particular program/system condition being monitored. The monitor alert instruction may be used in either the application mode (AM) or the control mode (CM) program to cause a software monitor alert function to be invoked in the engine under control of a 1-bit monitor mode register provided within engine
5. The software monitor alert detection logic 6 is driven by the instruction decode of the monitor alert instruction and causes the following actions:

If the monitor mode register is set, execution of the instruction causes the instruction counter (IC) to be updated in the normal manner to the address immediately following the instruction and causes the setting of a program check condition. If the engine was in AM, this would result in a program status word (PSW) swap to CM at the same level. The control program would determine the cause of the AM program check to be a software monitor alert condition. It would then branch to an appropriate monitoring routine. I...